This invention relates to metal containers, and more particularly to container bottoms adapted for use in candle cans.
Candles are often merchandised in decorative containers to present a package attractive to the purchasing consumer. A number of factors impact the design of a successful can for a candle, and they cover a range of factors including economy and ease of manufactureability, decorativeness, ability to reliably contain the molten wax and overall safety, as examples.
In recent years there has been an explosive growth in the use of scented candles in homes and business. In home environments the aromas released by the scented candle wax burned by candlewicks frequently are selected for the seasonal ambiance their burning evokes. Lilac in the spring, rose in the summer, pine in the fall or winter or whatever fragrance suits ones fancy. In business settings there are those that believe the aromas selected have therapeutic values with some individuals believing that citrus aroma heightens mental acuity. Most everyone is familiar with glass candle holders now in common use. Even if the outsides of the glass are decoratively finished, when the candle wax is depleted the transparent nature of the glass reveals the burned out condition of the candle which is not attractive. Enter highly decorative finished metal cans that look beautiful at all stages of their life. Even when empty they are considered by many to be worthy of collection. The downside of using metal cans to accommodate burning candles is well known and derives from the fact that the thermally conductive nature of metal frequently allows transmission of harmful quantities of heat from not only the flame but from the heated and liquefied candle wax which heat passes through the can base to a support surface which may be damaged by the heat.
Candle flash-over is also a danger. As is known, flash-over can occur when the pool of wax in the bottom of a candle can becomes relatively shallow, the wick burns down to approach the shallow pool, the pool becomes hotter than normal, and ultimately may reach a self sustained combustion temperature at which the wax will burn without a need for a wick. The candle can may then reach temperatures significantly in excess of 600xc2x0 F. and thereby presents a significant fire hazard.
The engine that drives competition is the seemingly never ending effort to discover simpler and simpler manufacturing procedures that reduce unit cost and enhance competitive pricing. It is in response to this quest for simplification that the subject invention provides an answer.
Pappas, U.S. Pat. No. 5,842,850 describes various approaches to preventing flash-over. These approaches deal primarily with keeping the wick, i.e. the source of candle ignition, sufficiently above the floor of the candle container which makes the flame go out before the fuel exceeds its flash point temperature. The ""850 patent typically employs a candlewick sustainer wherein the wick is held in a bore formed in the sustainer. The bore which contains the wick is centrally disposed in a vertical column that is supported by a base made impervious to candle fuel which thereby ensures that no candle fuel can reach the wick through the base that supports the bore containing the candlewick. Because the wick must be in contact with the liquefied wax it burns, it follows that the height of the sustainer column determines when the wick will lose its supply of fuel. The ""850 patent indicates that the top end of the column extends above the floor of the candle container an amount sufficient to prevent flash-over. In several embodiments the ""850 patent includes a centrally disposed pedestal upon which is mounted the afore described candlewick sustainer. The ""850 patent notes that where the candle container is of stamped metal the pedestal can be stamped into the container during manufacture.
The subject invention distinguishes over the ""850 patent in a number of novel and beneficial ways, most significantly in the provision of a stamp formed can bottom that uniquely elevates the candlewick holder in a dish to deprive the candlewick of burnable wax and prevent possible flash-over, while it also serves as a means to locate the candlewick holder prior to filling the can with wax. The stamp formed bottom also isolates heated liquefied wax to an outer periphery of the can bottom remote from the candle flame.
The unique bottom structure furthermore elevates the burning wick in such a manner that there is provided an insulating air space centrally disposed beneath the burning wick and the stamp formed bottom. The unique bottom structure additionally provides an annular surface ring that engages any surface upon which the candle can is placed further ensuring a minimal transfer of heat through the bottom of the candle can which might scorch and mar the supporting surface.
This invention is directed to a candle can of the type normally filled with an ignitable fuel. The candle can includes an upstanding continuous sidewall that is integrally coupled to a stamp formed candle can bottom structure at an outer periphery of the candle can bottom structure. The integral coupling of the sidewall to the bottom structure establishes a can support ring to engage a support surface. The stamp formed can bottom structure is so formed so as to provide within the can an internally upwardly directed dome upon which a candlewick carrying element may be securely located on an apex region of the dome.
In a preferred embodiment of the invention the intersection of the sidewall and the upwardly directed dome of the can bottom structure establishes an annular internal volume of fuel separated by the dome from a candlewick flame near the end of both the candlewick life and the supply of fuel. This just described arrangement of an annular internal volume of fuel which surrounds the dome minimizes flash-over while also creating an annular ring supporting surface for the candle can base which reduces heat transfer from the candle fuel and flame to the support surface.
In the preferred embodiment the dome and its apex region are optimized to prevent accumulation of carbon balls or particles near the wick, thus avoiding another source of flash-over.
In another embodiment of the invention the dome has a cone shape or is provided with a uniform radius of curvature.
In yet another embodiment of the invention the dome entirely spans the can base.
It is therefore a primary object of this invention to provide a candle can which is economical to mass produce, yet includes an insulating and highly effective flash-over prevention safety bottom.
According to a particular aspect of the invention, it is an object of the invention to provide a safety bottom for a candle which substantially reduces the area of contact between the can with its supporting surface, positions the candle can support surface contact area remote from the flame, and provides a dome shape wick support structure to minimize the possibility of flash-over.
Another object is to provide a candle can bottom configuration, and a method for forming that configuration, which is adaptable to both deep drawn containers and containers having a seamed construction. In providing adaptability, it is a feature of the invention that the bottom configuration is adaptable to cylindrical and non cylindrical configurations, but in all cases provides a structure wherein a central wick support dome is raised above a candle floor base by means of a sloping connecting wall.
Thus it is a feature of the invention to provide a candle can bottom structure which can be readily stamp formed, either during a drawing process for forming a single piece can, or in manufacture of the can bottom, all without the danger of so-overstretching the material of the bottom so as to create the possibility of pinholes, leaks or tears.
It is yet another object of the invention to provide a specially formed candle can having a bottom configuration which has a relatively small area annular ring at its base, so that when the base rests on a surface, contact with that surface is limited to the annular ring and an insulating air space which keeps most of the can bottom out of contact with the supporting surface. In one embodiment of the invention the area of contact with the surface is further diminished by the inclusion in the annular ring of protuberances i.e. bumps that further space the candle can from the surface that supports the candle can.
It is a further feature that the annular ring is positioned in a portion of the can where the wax is least likely to melt, with a dome shaped wick support being arranged to prevent flash-over and limit melting of a thicker portion of the wax at the outer periphery of the can. In that regard, the peripheral base remains at a somewhat lower temperature, so as to avoid scorching the table or other supporting surface.
These and other aims, objectives, and features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: